Vulnerability-Lookup

UBUNTU-CVE-2026-49943 (CVE-2026-49943)

Vulnerability from osv_ubuntu – Published: 2026-06-02 17:16 – Updated: 2026-10-17 09:44 – Source website

Details

CZ.NIC BIRD Internet Routing Daemon through 2.19.0 contains a stack-based buffer overflow in the BGP AS_PATH mask matching implementation in nest/a-path.c. The as_path_match() function uses a fixed-size stack array of 2048 + 1 pm_pos entries, while parse_path() expands AS_PATH segments from a received BGP UPDATE without enforcing a corresponding capacity limit. When RFC 8654 BGP Extended Messages are enabled and a BIRD filter evaluates an AS path mask expression such as "bgp_path ~ [= ... =]", an established BGP peer can send a long AS_PATH containing more than 2048 expanded ASNs. This causes parse_path()/as_path_match() to write beyond the fixed stack buffer, resulting in a crash of the daemon. NOTE: reportedly, the Supplier's position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes.

Severity

6.3 (Medium)


                    
                      CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-49943	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-49943	REPORT
	https://www.openwall.com/lists/oss-security/2026/…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird",
            "binary_version": "1.5.0-4build1"
          },
          {
            "binary_name": "bird-bgp",
            "binary_version": "1.5.0-4build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "bird",
        "purl": "pkg:deb/ubuntu/bird@1.5.0-4build1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.5.0-4",
        "1.5.0-4build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird",
            "binary_version": "1.6.3-3"
          },
          {
            "binary_name": "bird-bgp",
            "binary_version": "1.6.3-3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "bird",
        "purl": "pkg:deb/ubuntu/bird@1.6.3-3?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.6.3-3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird",
            "binary_version": "1.6.8-1"
          },
          {
            "binary_name": "bird-bgp",
            "binary_version": "1.6.8-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "bird",
        "purl": "pkg:deb/ubuntu/bird@1.6.8-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.6.7-1",
        "1.6.8-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird2",
            "binary_version": "2.0.7-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "bird2",
        "purl": "pkg:deb/ubuntu/bird2@2.0.7-2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.5-1",
        "2.0.7-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird",
            "binary_version": "1.6.8-2.1"
          },
          {
            "binary_name": "bird-bgp",
            "binary_version": "1.6.8-2.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "bird",
        "purl": "pkg:deb/ubuntu/bird@1.6.8-2.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.6.8-2.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird2",
            "binary_version": "2.0.8-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "bird2",
        "purl": "pkg:deb/ubuntu/bird2@2.0.8-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.7-4.1",
        "2.0.8-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird",
            "binary_version": "1.6.8-2.1build2"
          },
          {
            "binary_name": "bird-bgp",
            "binary_version": "1.6.8-2.1build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "bird",
        "purl": "pkg:deb/ubuntu/bird@1.6.8-2.1build2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.6.8-2.1",
        "1.6.8-2.1build1",
        "1.6.8-2.1build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird2",
            "binary_version": "2.14-1build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "bird2",
        "purl": "pkg:deb/ubuntu/bird2@2.14-1build2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.12-7",
        "2.14-1",
        "2.14-1build1",
        "2.14-1build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird2",
            "binary_version": "2.17.1-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "bird2",
        "purl": "pkg:deb/ubuntu/bird2@2.17.1-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.16.1-1",
        "2.17-1",
        "2.17.1-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird3",
            "binary_version": "3.1.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "bird3",
        "purl": "pkg:deb/ubuntu/bird3@3.1.0-1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird2",
            "binary_version": "2.19.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "bird2",
        "purl": "pkg:deb/ubuntu/bird2@2.19.2-1?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.18-1",
        "2.18.1-1",
        "2.19.0-1",
        "2.19.1-1",
        "2.19.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird3",
            "binary_version": "3.3.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "bird3",
        "purl": "pkg:deb/ubuntu/bird3@3.3.2-1?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.0-1",
        "3.2.1-1",
        "3.3.0-1",
        "3.3.1-1",
        "3.3.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird2",
            "binary_version": "2.18-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "bird2",
        "purl": "pkg:deb/ubuntu/bird2@2.18-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.17.1-1",
        "2.17.2-1",
        "2.17.3-1",
        "2.17.3-2",
        "2.18-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bird3",
            "binary_version": "3.2.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "bird3",
        "purl": "pkg:deb/ubuntu/bird3@3.2.0-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.0-1",
        "3.1.4-1",
        "3.1.5-1",
        "3.1.5-2",
        "3.2.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "CZ.NIC BIRD Internet Routing Daemon through 2.19.0 contains a stack-based buffer overflow in the BGP AS_PATH mask matching implementation in nest/a-path.c. The as_path_match() function uses a fixed-size stack array of 2048 + 1 pm_pos entries, while parse_path() expands AS_PATH segments from a received BGP UPDATE without enforcing a corresponding capacity limit. When RFC 8654 BGP Extended Messages are enabled and a BIRD filter evaluates an AS path mask expression such as \"bgp_path ~ [= ... =]\", an established BGP peer can send a long AS_PATH containing more than 2048 expanded ASNs. This causes parse_path()/as_path_match() to write beyond the fixed stack buffer, resulting in a crash of the daemon. NOTE: reportedly, the Supplier\u0027s position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes.",
  "id": "UBUNTU-CVE-2026-49943",
  "modified": "2026-10-17T09:44:21Z",
  "published": "2026-06-02T17:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-49943"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-49943"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2026/06/02/2"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-49943"
  ]
}

CVE-2026-49943 (GCVE-0-2026-49943)

Vulnerability from cvelistv5 – Published: 2026-06-02 16:16 – Updated: 2026-06-02 18:24

Summary

Severity

6.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-02 18:20 UTC

CWE

CWE-121 - Stack-based Buffer Overflow

Assigner

mitre CNA under the mitre root

CNA scorecard E 29/100 over 2369 records in the last 180 days details

References

2 references

URL	Tags
https://bird.nic.cz
https://gitlab.nic.cz/labs/bird/-/blob/master/NEWS

Impacted products

1 product

Vendor	Product	Version
NIC	BIRD	Affected: 0 , ≤ 2.19.0 (semver) cpe:2.3:a:nic:bird::::::::

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-49943",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-02T18:20:11.710969Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-02T18:24:47.786Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "BIRD",
          "vendor": "NIC",
          "versions": [
            {
              "lessThanOrEqual": "2.19.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:nic:bird:*:*:*:*:*:*:*:*",
                  "versionEndIncluding": "2.19.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "CZ.NIC BIRD Internet Routing Daemon through 2.19.0 contains a stack-based buffer overflow in the BGP AS_PATH mask matching implementation in nest/a-path.c. The as_path_match() function uses a fixed-size stack array of 2048 + 1 pm_pos entries, while parse_path() expands AS_PATH segments from a received BGP UPDATE without enforcing a corresponding capacity limit. When RFC 8654 BGP Extended Messages are enabled and a BIRD filter evaluates an AS path mask expression such as \"bgp_path ~ [= ... =]\", an established BGP peer can send a long AS_PATH containing more than 2048 expanded ASNs. This causes parse_path()/as_path_match() to write beyond the fixed stack buffer, resulting in a crash of the daemon. NOTE: reportedly, the Supplier\u0027s position is that a fix is not being prioritized because all network operators should already be rejecting routes with unusually long attributes."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-121",
              "description": "CWE-121 Stack-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-02T16:19:03.910Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://bird.nic.cz"
        },
        {
          "url": "https://gitlab.nic.cz/labs/bird/-/blob/master/NEWS"
        }
      ],
      "x_generator": {
        "engine": "CVE-Request-form 0.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-49943",
    "datePublished": "2026-06-02T16:16:52.033Z",
    "dateReserved": "2026-06-02T16:16:51.394Z",
    "dateUpdated": "2026-06-02T18:24:47.786Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted